Murine T cells that lyse antibody-sensitized target cells. II. Enrichment of K cells from normal thymus by isokinetic density centrifugation

Effects of palmatine on BDNF/TrkB-mediated trigeminal neuralgia

Trigeminal neuralgia (TN), a sudden, needle-like pain in the distribution area of the trigeminal nerve, can seriously affect the physical and mental health of patients. In chronic pain conditions including TN, increased levels of brain-derived neurotrophic factor (BDNF) may enhance pain transmission. This study compares the effect of palmatine administration on the expression of BDNF and its receptor TrkB (tropomyosin receptor kinase B) in trigeminal ganglion cells of Sprague-Dawley rats in a sham versus TN model group. Within 14 days of surgery, the mechanical allodynia threshold of the TN group was significantly lower than that of the sham group, while the TN + palmatine group had a higher mechanical pain sensitivity threshold than the TN group (p < 0.05). Real-time quantitative PCR, immunohistochemistry, and immunofluorescence showed that BDNF and TrkB expression in the TN group was higher than that in the sham group, while palmatine treatment could reverse these changes. Western blotting showed that palmatine treatment could reduce the elevated phosphorylation of extracellular signal-regulated kinases 1/2 (ERK1/2) in TN rats. Thus, the BDNF/TrkB pathway may be involved in the pain transmission process of TN, and palmatine treatment may reduce pain transmission by inhibiting the BDNF/TrkB pathway and suppressing ERK1/2 phosphorylation.

In vitro effect of acetaldehyde on cell-mediated cytotoxicity by murine spleen cells

The effects of acetaldehyde in vitro on the lytic capacity of murine spleen cells have been evaluated in three systems: antibody-dependent cell-mediated cytotoxicity (ADCC), natural killer (NK) activity, and alloimmune cytotoxic T lymphocyte (CTL) activity. Acetaldehyde had a biphasic effect on ADCC. Concentrations less than 1 mM acetaldehyde potentiated ADCC. Concentrations greater than 1 mM produced a progressive decrease in lysis. The inhibitory effects were at the effector cell level and were partially irreversible. Preincubation experiments showed that inhibition of ADCC was both concentration and time-dependent. Preincubation of the spleen cells for short periods of time produced potentiated lysis by concentrations of acetaldehyde up to 10 mM. However, potentiation of lysis in preincubation and short term (4h) lytic assay experiments was more variable than longer term (18h) experiments in which the acetaldehyde was not removed by washing. NK activity and alloimmune CTL-mediated lysis were also inhibited by acetaldehyde. Concentrations of acetaldehyde up to 20 mM did not significantly decrease lymphocyte viability as determined by trypan blue exclusion. Acetaldehyde was lost from the reaction mixtures by first order kinetics with a rate constant of 0.5/hr. Thus, the final concentrations were 64-99.99% lower than the starting amounts.

In vitro effect of ethanol on cell-mediated cytotoxicity by murine spleen cells

The effects of ethanol on murine spleen cell-mediated lysis have been studied. Concentrations of 5.5-176 mM ethanol produced progressive inhibition of antibody-dependent cell-mediated cytotoxicity (ADCC). Binding of spleen cells to antibody-sensitized target cells was not inhibited by comparable concentrations of ethanol. Kinetic analysis revealed decreased rates of lysis with increasing concentrations of ethanol. Changes of effector to target cell ratios revealed an inhibition of maximum lysis and decreased lytic efficiency in the presence of 88 mM ethanol. Preincubation experiments showed the inhibitory effect of ethanol to be reversible. Macrophage-depleted spleen cells appeared to be as susceptible to inhibition by ethanol as unfractionated spleen cells. Ethanol also inhibited natural killer and alloimmune cytotoxic T cell activity. The ADCC data were analysed by using a mathematical model which incorporates the kinetics of lysis, dose-response relationships, heterogeneity of the lytic effectors, reversibility of inhibition and ethanol loss during incubation. An inhibition constant (KI) of 373 mM-2 when two ethanol molecules interact with the site of inhibition was calculated. 50% inhibition of lysis is produced by 52 mM (0.24%) ethanol. The results are consistent with a model which assumes that lysis is due to a critical number of interactions which ultimately trigger the lytic event. Alcohol interferes with lysis by reacting with sites which are required for triggering the lytic event. Although the molecular details of the mechanism of inhibition are as yet undefined, we infer that ethanol inhibits ADCC at the programming for lysis or the lethal hit stages.